The movement of people towards cities has accelerated in the past 40 years, particularly in the less developed regions, and the share of the global population living in urban areas has increased from one third in 1960 to 47% (2.8 billion people) in 1999. The world's urban population is now growing by 60 million persons per year, about three times the increase in the rural population.

Increasing urbanisation results about equally from births in urban areas and from the continued movement of people from the rural surround. These forces are also feeding the sprawl of urban areas as formerly rural peri-urban settlements become incorporated into nearby cities and as secondary cities, linked by commerce to larger urban centres, grow larger.

The proportion of people in developing countries who live in cities has almost doubled since 1960 (from less than 22% to more than 40%), while in more-developed regions the urban share has grown from 61% to 76%. There is a significant association between this population movement from rural to urban areas and declines in average family size.

Asia and Africa remain the least urbanised of the developing regions (less than 38% each). Latin America and the Caribbean is more than 75% urban, a level almost equal to those in Europe, Northern America and Japan (all are between 75 and 79%).

Urbanisation is projected to continue well into the next century. By 2030, it is expected that nearly 5 billion (61%) of the world's 8.1 billion people will live in cities. The less-developed regions will be more than 57% urban. Latin America and the Caribbean will actually have a greater percentage of inhabitants living in cities than Europe will.

Globally, the number of cities with 10 million or more inhabitants is increasing rapidly, and most of these new 'megacities' are in the less-developed regions. In 1960, only New York and Tokyo had more than 10 million people. By 1999, there were 17 cities of more than 10 million people around the world, 13 of these were in less-developed regions. It is projected that there will be 26 megacities by 2015, 22 in less-developed regions (18 will be in Asia); more than 10% of the world's population will live in these cities, up from just 1.7% in megacities in 1950.

(http://www.unesco.org/education/tlsfl/mods/theme_popups/mod/3101s009.html)

The word "declines" in paragraph 3 most closely means